The way to find out the code of your own textbook on the English website of Tsinghua Society is: You can find it on the English official website of Tsinghua Society, dear. Tsinghua University authorized library. Tsinghua refers to Tsinghua University Education Research Press, and the codes of its textbooks can be found in the library authorized by Tsinghua University. Scan two Wei codes in the book, click "activate", then click "activate the teaching material" and click "return to my course" to enter the study.